This invention relates to fuel supply systems for diesel engines and, more particularly, to such systems provided with a fuel additive injector.
Diesel fuels are typically rated by cetane numbers, and a given diesel engine, when fully warmed up, will operate quite satisfactorily on a fuel having a given cetane number. However, when cold, and operating on fuel of a given cetane number, many engines will emit excessive quantities of so-called "white smoke" until the engine has fully warmed up. The emission of such white smoke is highly undesirable in terms of pollution problems. In order to overcome the problem, the prior art has resorted to the mixing of fuel additives which are cetane number increasers with the fuel in the main fuel tank, the amount of such additive being determined by the necessary increase of the cetane number required to avoid undesirable white smoke emission levels.
This approach, while quite successful in terms of the ultimate result of the reduction of white smoke emission, is economically prohibitive since the additives are costly and continue to be consumed even when not required after the engine is warmed up due to their presence in the main fuel tank.